Mario Andretti says he is "very interested" to find out how George Russell deals with the move to Mercedes for 2022, arguing that he has "huge shoes to fill" by replacing Valtteri Bottas as Lewis Hamilton's new teammate.
Former GP3 and F2 champion Russell makes the switch to Mercedes for F1's new era of technical regulations after spending three seasons with Williams – initially at the back of the grid and more recently in the midfield.
In 2020, Russell was given an early opportunity to drive for Mercedes at the Sakhir Grand Prix, where he replaced the unwell Hamilton and challenged for pole position and victory until misfortune late in the race.
Russell replaces Bottas as Hamilton's new teammate
Despite Russell's form at Williams, and his eye-catching one-off appearance for Mercedes, Andretti would not be surprised if things become "a little more difficult" as the 23-year-old adapts to life at the Silver Arrows.
Mercedes have won eight Constructors' world titles in a row, with the last five notched up between Hamilton and Bottas, who has joined Alfa Romeo.
"He has some huge shoes to fill! Not only vis-a-vis Lewis, but also vis-as-vis Valtteri, who was a strong, valuable teammate," 1978 World Champion Andretti told RacingNews365.com in an exclusive interview.
"We have seen what George did in Bahrain, on a one-off situation, so you would expect that he will show really strong [performance].
"But we always wait to see. You can draw a lot of conclusions, but until it's proven... Sometimes it's a one-off that really works out and then when you're really in there it becomes a little more difficult."
Russell set for "biggest opportunity of his life"
Russell has repeatedly described seven-time World Champion Hamilton, 14 years his senior, as "the greatest of all time", and Andretti pointed out just how important the coming season could be in shaping the youngster's F1 career.
"It's just another thing, another area to look forward to and to see how it plays out," Andretti went on to comment.
"I think it's the biggest opportunity of his life, to really shine in the sport, with the top team at the moment, so we all wish him well, for sure."
Russell's arrival at Mercedes marks only the third permanent driver change the team have made since returning to F1 as a manufacturer team in 2010, having initially fielded Michael Schumacher and Nico Rosberg, before introducing Hamilton and Bottas.
F1 Podcast: How real is the threat that Hamilton will leave F1?
F1 journalists Dieter Rencken, Thomas Maher and Mike Seymour weigh up the possibility that Lewis Hamilton might leave F1 behind, as well as analysing what might be uncovered during the FIA investigation into the 2021 Abu Dhabi Grand Prix.